JP6313140B2 - Communication device and multi-hopping network - Google Patents

Description

  Embodiments described herein relate generally to a communication device and a multi-hopping network.

  Conventionally, a method of forming a plurality of communication paths from a communication device to a server (root node) is known as a method of forming a communication path in a multi-hop network. There is also known a method for maintaining communication quality by switching a communication path used for transfer of communication data at predetermined time intervals from a plurality of communication paths formed by the method.

  However, in the above conventional method, the communication path from the communication device to the predetermined server can be switched. However, when the predetermined server is switched to another server, the predetermined server is switched according to the server switching. It was not possible to switch the communication path to a communication path to another server.

JP 2008-135817 A

P. Thubert et al., “RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks,” IETF, RFC6550, 2012

  Provided are a communication device and a multi-hopping network capable of switching a communication path according to switching of a route node.

  A communication device according to an embodiment forms a multi-hop network. The communication device includes a holding unit, a storage unit, a switching unit, and a control unit. The holding unit holds communication data. The storage unit stores path information including an identifier for specifying a communication path and destination information indicating a destination of communication data on the communication path. The switching unit switches a communication path used for communication data transfer based on the path information stored in the storage unit. The control unit transfers the communication data to the destination of the communication path switched by the switching unit.

The block diagram which shows the function structure of the communication apparatus which concerns on 1st Embodiment. The figure which shows an example of a multihop network. The table | surface which shows an example of route information. The block diagram which shows the hardware constitutions of the communication apparatus which concerns on 1st Embodiment. The figure which shows an example of a multihop network. 6 is a flowchart showing the operation of the communication apparatus according to the first embodiment. The block diagram which shows the function structure of the communication apparatus which concerns on 2nd Embodiment. The flowchart which shows operation | movement of the communication apparatus which concerns on 2nd Embodiment. The block diagram which shows the function structure of the communication apparatus which concerns on 3rd Embodiment. The flowchart which shows operation | movement of the communication apparatus which concerns on 3rd Embodiment. The sequence diagram which shows operation | movement of the communication apparatus which concerns on 4th Embodiment. The figure which shows an example of the format of DIO. The flowchart which shows operation | movement of the communication apparatus which concerns on 4th Embodiment. The figure which shows an example of DODAG information. The figure which shows an example of DODAG information.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
A communication device 10 according to the first embodiment will be described with reference to FIGS. The communication device 10 according to the present embodiment constitutes a multihop network. The multi-hop network is a network having a tree-type topology configured by a plurality of communication devices (nodes). In a multi-hop network, various types of information are transferred between a plurality of communication devices according to a communication path. In the present embodiment, the communication device 10 switches the communication route in use to a new communication route to another route node acquired from another communication device.

  First, the functional configuration of the communication apparatus 10 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a functional configuration of a communication device 10 according to the present embodiment. As illustrated in FIG. 1, the communication device 10 includes a communication data holding unit 1, a communication path storage unit 2, a communication path switching unit 3, and a communication control unit 4.

  The communication data holding unit 1 (hereinafter referred to as “holding unit 1”) holds communication data. Communication data is any data that is intended for transfer in a multi-hop network. The communication data held in the holding unit 1 is transferred from the communication device 10 to another communication device constituting the multi-hop network according to the communication path.

  The communication path storage unit 2 (hereinafter referred to as “storage unit 2”) stores path information. The route information is information set for each communication route. The route information includes a route identifier, destination information, interface information, and priority information, but is not limited thereto.

  The path identifier is information that identifies each communication path. When an ID is assigned to each communication path, the ID can be used as a path identifier. Hereinafter, the communication path specified by ID00 (00 is arbitrary) is referred to as communication path 00.

  When there is only one communication path from the communication device 10 to the root node (final destination communication device), the address of the root node can be used as the route identifier. Specifically, a server address, a border router address, or the like can be used as the path identifier.

  Here, FIG. 2 is a diagram illustrating an example of a multi-hop network configured by the communication apparatus 10. The multi-hop network in FIG. 2 includes four communication devices 10-13. In FIG. 2, the root node is the communication device 13. There are two communication paths from the communication apparatus 10 to the root node: a communication path 01 that passes through the communication apparatus 11 and a communication path 02 that passes through the communication apparatus 12.

  As shown in FIG. 2, when there are two communication paths from the communication device 10 to the root node, the communication path cannot be specified only by the root node address. In such a case, information identifying each of a plurality of communication paths to the root node may be used together with the root node address as the path identifier. For example, RPL Instance ID can be used as such information. The RPL Instance ID will be described later.

  The destination information is information indicating a communication data destination set for each communication path, that is, a communication device that is a transfer destination of the communication data. For example, in the case of the communication path 01 in FIG. 2, the destination of the communication device 10 is the communication device 11. Hereinafter, “destination” is referred to as “next hop”. The destination information is, for example, the address of the communication device that is the next hop.

  The interface information is information indicating a communication interface set for each communication path or for each next hop. As the interface information, an ID or type assigned to each communication interface included in the communication device 10 can be used. Note that when the communication device 10 includes only one communication interface, the storage unit 2 may not store the interface information.

  The priority information is information indicating the priority of whether or not to use the communication path for communication data transfer. The priority indicated by the priority information may be a binary priority corresponding to “use” and “not use”, or may be a multi-value priority. In the following, it is assumed that priority 1 corresponds to “use” and priority 0 corresponds to “not use”. 1 and 0 may be reversed.

  Here, FIG. 3 is a table showing an example of route information stored in the storage unit 2 of the communication apparatus 10 of FIG. According to the route information of FIG. 3, the communication device 10 uses the communication route 01 and transfers communication data to the communication device 11 wirelessly. As illustrated in FIG. 3, the storage unit 2 may store route information of a plurality of communication routes.

  The communication path switching unit 3 (hereinafter referred to as “switching unit 3”) switches a communication path used for transfer of communication data based on the path information stored in the storage unit 2. In the present embodiment, the switching unit 3 acquires route information from another communication device, compares the acquired route information with the route information stored in the storage unit 2, and selects a communication route to be used. When the switching unit 3 selects a communication route to be used, the switching unit 3 changes the priority of the selected communication route to 1, and changes the priority of the other communication route stored in the storage unit 2 to 0. Thereby, the communication path is switched. A method for selecting a communication path by the switching unit 3 will be described later.

  The communication control unit 4 (hereinafter referred to as “control unit 4”) uses the communication path switched by the switching unit 3 to transfer communication data. First, the control unit 4 refers to the priority information stored in the storage unit 2 and acquires the route information of the priority 1. Next, the control unit 4 refers to the destination information of the acquired route information and acquires the next hop. And the control part 4 transfers the communication data hold | maintained at the holding | maintenance part 1 to the acquired next hop via a communication interface. The communication data transferred by the communication control unit 4 may be communication data received from another communication device, or may be communication data generated by the communication device 10.

  When the interface information is stored in the storage unit 2, the control unit 4 refers to the interface information and acquires the communication interface set for the communication path to be used. The control unit 4 transfers the communication data via the acquired communication interface. Thereby, even if it is a case where the communication apparatus 10 is provided with a some communication interface, a communication interface can be used properly according to a communication path | route.

  Next, the hardware configuration of the communication apparatus 10 according to the present embodiment will be described with reference to FIG. The communication device 10 according to the present embodiment includes a computer and is a device capable of wireless or wired data communication. Although the communication apparatus 10 is a server, a router, a sensor, a smart phone, and a smart meter, for example, it is not restricted to this. In any case, the communication device 10 implements each functional configuration described above by executing a program with a computer.

  Here, FIG. 4 is a block diagram showing a hardware configuration of the communication apparatus 10 according to the present embodiment. As shown in FIG. 4, the communication device 10 includes a CPU 101, an input device 102, a display device 103, a communication interface 104, a main storage device 105, and an external storage device 106, which are connected via a bus 107. Are connected to each other.

  A CPU (Central Processing Unit) 101 executes a communication program on the main storage device 105. The communication program is a program that realizes each functional configuration of the communication device 10. When the CPU 101 executes the communication program, each functional configuration described above is realized.

  The input device 102 is a device for inputting data and commands to the communication device 10 from the outside. The input device 102 may be a device for direct input by the user, such as a keyboard, a mouse, and a touch panel. Further, the input device 102 may be a device such as a USB that enables input from an external device, or software.

  The display device 103 is a display that displays a video signal output from the communication device 10. The display device 103 is, for example, an LCD (liquid crystal display), a CRT (CRT), and a PDP (plasma display), but is not limited thereto. Communication data held in the holding unit 1 and route information stored in the storage unit 2 can be displayed by the display device 103.

  The communication interface 104 is a device for the communication device 10 to communicate with other communication devices constituting the multi-hop network. The communication device 10 performs wireless communication or wired communication with another communication device through a communication interface 104 using a predetermined communication method. For example, the communication device 10 may include a plurality of communication interfaces having the same or different standards and frequency bands. The communication device 10 may include a wireless interface and a wired communication interface.

  The main storage device 105 stores a communication program, data necessary for executing the communication program, data generated by executing the communication program, and the like when executing the communication program. The communication program is expanded and executed on the main storage device 105. The main storage device 105 is, for example, a RAM, a DRAM, or an SRAM, but is not limited thereto. The holding unit 1 and the storage unit 2 are constructed on at least one of the main storage device 105 and the external storage device 106. The main storage device 105 may store a computer OS, BIOS, and various middleware.

  The external storage device 106 stores a communication program, data necessary for executing the communication program, data generated by executing the communication program, and the like. These programs and data are read to the main storage device 105 when the communication program is executed. The external storage device 106 is, for example, a hard disk, an optical disk, a flash memory, and a magnetic tape, but is not limited thereto.

  The communication program may be installed in advance in the computer or may be stored in a storage medium such as a CD-ROM. The communication program may be uploaded on the Internet. The communication device 10 may be configured without the input device 102 and the display device 103.

  Next, the operation of the communication apparatus 10 according to the present embodiment will be described with reference to FIGS. Here, FIG. 5 is a diagram illustrating an example of a multi-hop network configured by the communication device 10. FIG. 6 is a flowchart showing the operation of the communication apparatus 10 according to the present embodiment.

  The multi-hop network of FIG. 5 includes five communication devices 10-14. In FIG. 5, communication devices 13 and 14 are servers (root nodes) that collect communication data. It is assumed that the storage unit 2 of the communication device 10 stores the path information illustrated in FIG. 3 at the start of the operation. Further, the flowchart of FIG. 6 shows an operation in accordance with a policy in which a high priority is set for newly received route information.

  In step S <b> 1, the switching unit 3 acquires route information from another communication device via the communication interface 104. The other communication device may be the communication device 11 that is the next hop of the communication device 10 or the communication device 13 that is a server. Note that the route information acquired by the communication device 10 may not include priority information.

  In step S2, the switching unit 3 determines whether the acquired route information is new route information. The new route information is route information that is not stored in the storage unit 2. Specifically, the switching unit 3 compares the acquired route identifier of the route information with the identifier of the route information stored in the storage unit 2. When the route identifier of the acquired route information and the identifier of the route information stored in the storage unit 2 do not match, the switching unit 3 determines the acquired route information as new route information.

  If the acquired route information is not new route information (NO in step S2), that is, if the acquired route information is the route information of the communication route 01 or the communication route 02, the process ends. Thereafter, the control unit 4 transfers communication data using the communication path 01.

  On the other hand, when the acquired route information is new route information (YES in step S3), the process proceeds to step S3. Here, it is assumed that the new route information acquired by the switching unit 3 is the route information of the communication route 03. The communication path 03 is a communication path indicated by a broken line in FIG. The route node of the communication path 03 is the communication device 14, and the next hop is the communication device 12.

  In step S3, the switching unit 3 selects the communication path 03 having new path information as a communication path used for transfer of communication data.

  In step S4, the storage unit 2 stores the route information of the communication route 03 selected by the switching unit 3. When the priority information is not included in the route information of the communication route 03, the priority information is a null value.

  In step S5, the switching unit 3 changes the priority of the communication path 03 to 1. Further, the switching unit 3 changes the priority of the communication paths 01 and 02 to 0. As a result, the communication path to be used is switched to the communication path 03.

  Thereafter, the control unit 4 transfers communication data using the communication path 03. That is, the control unit 4 transfers the communication data to the communication device 12 that is the next hop of the communication path 03. Further, the control unit 4 may transfer the acquired route information to another communication device after the communication route is switched.

  As described above, according to the present embodiment, the communication device 10 can switch the communication route to be used based on the route information acquired from another communication device. Therefore, when the root node is switched, the communication path used by the communication apparatus 10 can be switched by inputting the path information to the new switched root node to the communication apparatus 10. For this reason, even if a failure occurs in the transfer of communication data from the communication device 10 to the root node due to a server abnormality or deterioration in connectivity between the communication devices, the root node is switched to another communication device. Thus, communication data of the communication device 10 can be easily collected.

  Specifically, when a failure occurs in the transfer of communication data from the communication device 10 to the server 13, the alternative server 14 is connected to the multi-hop network. Then, the route information of the communication route 03 is input to the communication device 10 from the alternative server 14 directly or via another communication device 12. As a result, the communication apparatus 10 automatically switches the communication path to be used to the communication path 03 and transfers the communication data to the alternative server 14. Therefore, the communication data of the communication device 10 can be collected by the alternative server 14.

  In the present embodiment, when the route information includes priority information indicating multi-value priority, the switching unit 3 selects a communication route having a higher priority among communication routes having new route information as communication data. It may be selected as a communication path used for transfer. The communication path having a high priority here is, for example, a communication path having a priority higher than a predetermined value, a communication path having a higher priority than a communication path having path information stored in the storage unit 2, or a communication in use. It is a communication path having a higher priority than the path.

(Second Embodiment)
A communication device 10 according to the second embodiment will be described with reference to FIGS. 7 and 8. The communication device 10 according to the present embodiment switches the communication path according to the switching instruction information.

  First, the functional configuration of the communication apparatus 10 according to the second embodiment will be described with reference to FIG. FIG. 7 is a block diagram illustrating a functional configuration of the communication apparatus 10 according to the present embodiment. As illustrated in FIG. 7, the communication device 10 includes a switching instruction information acquisition unit 5. Other configurations are the same as those of the first embodiment.

  The switching instruction information acquisition unit 5 (hereinafter referred to as “acquisition unit 5”) acquires switching instruction information. The switching instruction information is information that instructs to switch a communication path in use to a predetermined communication path. Hereinafter, a communication path for which switching instruction information is instructed is referred to as a switching instruction path. The switching instruction information includes a path identifier that identifies the switching instruction path. As the switching instruction information, for example, information obtained by changing a part of the route information so as to satisfy a predetermined condition can be used. Specifically, DODAG information in which the rank value in RPL is set to a predetermined value can be used as switching instruction information. The DODAG information will be described later. Further, route information in a predetermined format can be used as the switching instruction information, but the switching instruction information is not limited to this.

  The hardware configuration of the communication apparatus 10 according to the present embodiment is the same as that of the first embodiment. The functional configuration of the acquisition unit 5 is realized by the computer executing the communication program.

  Next, the operation of the communication apparatus 10 according to the present embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing the operation of the communication apparatus 10 according to the present embodiment. In the following, it is assumed that the communication device 10 forms the multi-hop network of FIG. 5, stores the route information of the communication routes 01 and 03 and uses the communication route 01 at the start of operation.

  In step S <b> 6, the acquisition unit 5 acquires switching instruction information from information received by the communication device 10 from another communication device via the communication interface 104. The other communication device may be the communication device 11 that is the next hop of the communication device 10 or the communication device 13 that is a server.

  In step S <b> 7, the switching unit 3 determines whether the switching instruction path of the switching instruction information acquired by the acquiring unit 5 is a communication path in use. The switching unit 3 compares the path identifier of the switching instruction path with the path identifier that specifies the communication path in use, and determines that the switching instruction path is a communication path in use when the two match.

  If the switching instruction path is a communication path in use (YES in step S7), that is, if the switching instruction path is the communication path 01, the process ends. Thereafter, the control unit 4 transfers communication data using the communication path 01.

  On the other hand, if the switching instruction route is not a busy communication route (NO in step S7), that is, if the switching instruction route is the communication routes 02 and 03, the process proceeds to step S8.

  In step S <b> 8, the switching unit 3 determines whether the switching instruction route is a communication route in which route information is stored in the storage unit 2. The switching unit 3 compares the route identifier of the switching instruction route with the route identifier of the route information stored in the storage unit 2, and if both match, the route information of the switching instruction route is stored in the storage unit 2. It is determined that

  If the path information of the switching instruction path is not stored in the storage unit 2 (NO in step S8), that is, if the switching instruction path is the communication path 02, the process ends. Thereafter, the control unit 4 transfers communication data using the communication path 01.

  On the other hand, if the path information of the switching instruction path is stored in the storage unit 2 (YES in step S8), that is, if the switching instruction path is the communication path 03, the process proceeds to step S9.

  In step S9, the switching unit 3 selects the switching instruction path 03 as a communication path used for communication data transfer.

  In step S10, the switching unit 3 changes the priority of the switching instruction path 03 to 1. Further, the switching unit 3 changes the priority of the communication path 01 to 0. As a result, the communication path to be used is switched to the communication path 03.

  Thereafter, the control unit 4 transfers communication data using the communication path 03. That is, the control unit 4 transfers the communication data to the communication device 12 that is the next hop of the communication path 03. Further, the control unit 4 may transfer the switching instruction information to another communication apparatus after the communication path is switched.

  As described above, according to the present embodiment, the communication device 10 can switch the communication path to be used based on the switching instruction information acquired from another communication device. Since the communication path to be switched is stored in advance in the storage unit 2, the time for storing the communication path information in the storage unit 2 is not required, and the communication path can be switched in a short time.

(Third embodiment)
A communication device 10 according to the third embodiment will be described with reference to FIGS. 9 and 10. The communication apparatus 10 according to the present embodiment switches the communication path according to the connectivity of the communication path.

  First, the functional configuration of the communication apparatus 10 according to the third embodiment will be described with reference to FIG. FIG. 9 is a block diagram illustrating a functional configuration of the communication apparatus 10 according to the present embodiment. As illustrated in FIG. 9, the communication device 10 includes a connection information collection unit 6. Other configurations are the same as those of the first embodiment.

  The connection information collection unit 6 (hereinafter referred to as “collection unit 6”) collects connection information. The connection information is information indicating the connectivity of the communication path. The connection information may be information indicating the presence or absence of connectivity, or may be information indicating the strength of connectivity. As the connection information, for example, the number of times communication data transfer failed or ICMP error notification can be used, but the connection information is not limited to this.

  The hardware configuration of the communication apparatus 10 according to the present embodiment is the same as that of the first embodiment. The functional configuration of the collection unit 6 is realized by the computer executing the communication program.

  Next, the operation of the communication apparatus 10 according to the present embodiment will be described with reference to FIG. FIG. 10 is a flowchart showing the operation of the communication apparatus 10 according to the present embodiment. In the following, it is assumed that the communication device 10 configures the multi-hop network of FIG. 5, stores the route information of the communication routes 01, 02, and 03 and uses the communication route 01 at the start of operation. Further, it is assumed that the communication paths 01 and 02 cannot be connected and the communication path 03 can be connected.

  In step S11, the collection unit 11 collects connection information indicating the connectivity of the communication path 01 being used. The collection unit 6 may collect connection information from other communication devices, or may generate the connection information from history information of communication data transfer results. The other communication device may be the communication device 11 that is the next hop of the communication device 10 or the communication device 13 that is a server.

  In step S <b> 12, the switching unit 3 determines whether the communication path 01 in use is connectable based on the connection information collected by the collection unit 6. That is, the switching unit 3 determines whether communication data can be transferred to the communication device 13 that is a server using the communication path 01 in use.

  For example, the switching unit 3 performs the determination by comparing the connectivity indicated by the connection information with a predetermined threshold value. For example, when the connection information is the number of times that the transfer of communication data has failed in a predetermined period, the switching unit 3 compares the number of times of transfer failure with a predetermined threshold value. It is determined that the path 01 cannot be connected. Alternatively, the switching unit 3 may determine whether or not connection is possible based on the presence / absence of an ICMP error notification.

  If the communication path 01 in use is connectable (YES in step S12), the process ends. Thereafter, the control unit 4 transfers communication data using the communication path 01.

  On the other hand, when the communication path 01 in use cannot be connected (NO in step S12), the process proceeds to step S13.

  In step S <b> 13, the switching unit 3 determines whether path information of a communication path other than the communication path in use (other communication paths) is stored in the storage unit 2.

  If route information of another communication route is not stored in the storage unit 2 (NO in step S13), the process ends. Thereafter, the communication device 10 is disconnected from the multi-hop network. Alternatively, the communication device 10 may perform communication using a new communication path by the method described in the first embodiment.

  On the other hand, when route information of another communication route is stored in the storage unit 2 (YES in step S13), the process proceeds to step S14.

  In step S <b> 14, the switching unit 3 determines whether another communication path whose path information is stored in the storage unit 2 can be connected based on the connection information collected by the collection unit 6. This determination can be performed by the same method as in step S12. The connection information of other communication paths may be collected in step S11 or may be collected in step S14.

  If all the other communication paths stored in the storage unit 2 are not connectable (NO in step S14), the process ends. Thereafter, the communication device 10 is disconnected from the multi-hop network. Alternatively, the communication device 10 may perform communication using a new communication path by the method described in the first embodiment.

  On the other hand, when at least one of the other communication paths stored in the storage unit 2 is connectable (YES in step S14), the process proceeds to step S15.

  In step S15, the switching unit 3 selects the communication path 03 determined to be connectable as a communication path used for transfer of communication data. When there are a plurality of other communication paths that can be connected, the switching unit 3 determines, for example, the communication path with the best connectivity based on the connection information or the communication path with the smallest number of hops to the server (root node). Select.

  In step S <b> 16, the switching unit 3 changes the priority of the selected communication path 03 to 1. In addition, the switching unit 3 changes the priority of the communication paths 01 and 02 to 0. As a result, the communication path to be used is switched to the communication path 03.

  Thereafter, the control unit 4 transfers communication data using the communication path 03. That is, the communication data is transferred to the communication device 12 that is the next hop of the communication path 03.

  As described above, according to the present embodiment, when the connectivity of the communication path in use is not high or low, the communication device 10 automatically selects another communication path that can be connected to the server (root node). Can communicate with.

(Fourth embodiment)
A communication device 10 according to the fourth embodiment will be described with reference to FIGS. The communication device 10 according to the present embodiment configures a multi-hop network that employs RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) as a communication protocol.

  First, a method for setting a communication path of the communication device 10 when the communication device 10 participates in the multi-hop network configured by the communication devices 11 to 13 of FIG. 2 will be described with reference to FIG. In the following, it is assumed that the communication devices 11 and 12 are adjacent nodes of the communication device 10 and the communication device 13 is a root node (server).

  The communication device 10 transmits DIS (DODAG Information Solicitation) to the adjacent nodes (communication devices) 11 and 12 by multicast. The DIS is a message requesting the received node to transmit a DIO (DODAG Information Object). The adjacent nodes 11 and 12 that have received the DIS transmit DIO to the communication device 10.

  The DIO is a message for notifying DODAG information related to DODAG (Destination Oriented Directed Acyclic Graph) which is a topology of a multi-hop network. Here, FIG. 12 is a diagram illustrating an example of a DIO format. As shown in FIG. 12, the DIO notifies the RPL Instance ID, Version number, Rank, G, MOP, Pfr, DTSN, Flags, and DODAGID as DODAG information.

  RPL Instance ID is an identifier given to each instance of RPL. The data length of the RPL Instance ID is 1 byte. The RPL Instance ID indicates a global instance when the most significant bit is 0, and indicates a local instance when it is 1. The RPL Instance ID can be used as a route identifier.

  Version number (version number) is the version of each communication path. The data length of the version number is 1 byte. The version number can be used as a path identifier.

  Rank (rank value) is the number of hops to the root node. The smaller the rank value, the closer to the root node. The rank value of the root node is 0. In RPL, a communication path is set based on this rank value. The data length of Rank is 2 bytes.

  G indicates connectivity with the root node. The data length of G is 1 bit. G can be used as connection information in the third embodiment.

  DODAGID is the IPv6 address of the root node. The data length of DODAGID is 16 bytes. DODAGID can be used as a route identifier.

  The communication device 10 that has received the DIO as described above from the adjacent nodes 11 and 12 sets the communication path 01 to the root node (communication device) 13 based on the rank value of each adjacent node 11 and 12 included in the DIO. Set. When the communication apparatus 10 sets the communication path 01, the communication apparatus 10 transmits a DAO (Destination Advertisement Object) to the root node 13 of the set communication path 01. DAO is a message notifying the next hop (parent node) of the communication device 10. By receiving DAO, the root node 13 can acquire the next hop of the communication device 10.

  The root node 13 that has received DAO transmits DAO_ACK to the communication device 10. DAO_ACK is a message notifying that DAO has been received. When the communication device 10 receives DAO_ACK, the setting of the communication path 01 is completed. Thereafter, the communication apparatus 10 can transfer communication data using the communication path 01.

  When setting the communication path 01, the communication device 10 stores the DODAG information notified by the DIO received from the adjacent nodes 11 and 12 in the storage unit 2 as the path information.

  Next, operation | movement of the communication apparatus 10 which concerns on this embodiment is demonstrated with reference to FIGS. FIG. 13 is a flowchart showing the operation of the communication apparatus 10 according to the present embodiment. In the following, it is assumed that the communication device 10 has set a communication path to the server A (root node) and stores the DODAG information (DODAG1) used when setting the communication path. In this embodiment, the route information includes two levels of priority, and the most significant bit of the RPL Instance ID represents the priority of the route information.

  FIG. 14 is a diagram illustrating an example of DODAG1 (path information) stored in the storage unit 2 of the communication device 10. As illustrated in FIG. 14, DODAG1 includes an RPL Instance ID, a DODAGID, a version number, a rank value of the communication device 10, and an address and rank value of an adjacent node. A communication device with a rank value of 0 is server A. According to FIG. 14, the address of server A is 2001: 1. DODAGID is the address of server A.

  When the communication device 10 receives DIO from another communication device, the communication device 10 starts a communication path switching operation shown in FIG.

  In step S17, the acquisition unit 5 acquires DODAG information (DODAG2) notified by the received DIO.

  In step S18, the switching unit 3 compares the path identifier included in DODAG1 stored in the storage unit 2 with the path identifier included in the acquired DODAG information, and determines whether DODAG2 is new path information. To do.

  Here, FIG. 15 is a diagram illustrating an example of DODAG information (DODAG2) of a communication path having the server B as a root node. When the communication apparatus 10 acquires DODAG2, the switching unit 3 uses at least one of the RPL Instance ID, DODAGID, version number, and node address (server A and B addresses) of DODAG1 and DODAG2 as a path identifier. The determination can be performed. For example, when the path identifier is DODAGID, the DODAGID of DODAG1 is 2001: 1, and the DODAGID of DODAG2 is 2002 :: 2, so the switching unit 3 determines that DODAG2 is new path information.

  If the acquired DODAG2 is not new route information (NO in step S18), the process ends. Thereafter, the control unit 4 transfers the communication data by using the communication path set by DODAG1. Therefore, the communication data of the communication device 10 is transferred to the server A.

  On the other hand, when the acquired DODAG2 is new route information (YES in step S18), the process proceeds to step S19.

  In step S19, the storage unit 2 stores the acquired DODAG2.

  In step S20, the switching unit 3 determines whether the instance of DODAG2 is local. That is, the switching unit 3 determines whether the most significant bit of the RPL Instance ID of DODAG2 is 1.

  If the instance of DODAG2 is global (NO in step 18), that is, if the most significant bit of the RPL Instance ID of DODAG2 is 0, the process ends. Thereafter, the control unit 4 transfers the communication data by using the communication path set by DODAG1. Therefore, the communication data of the communication device 10 is transferred to the server A.

  On the other hand, if the instance of DODAG2 is local (YES in step 18), that is, if the most significant bit of the RPL Instance ID of DODAG2 is 1, the process proceeds to step S21.

  In step S21, the switching unit 3 changes the priority of DODAG2 to 1. Further, the switching unit 3 changes the priority of DODAG1 to 0. As a result, the communication path to be used is switched to the communication path set by DODAG2.

  Thereafter, the control unit 4 transfers the communication data using the communication path set by DODAG2. Accordingly, the communication data of the communication device 10 is transferred to the server B. The control unit 4 may transfer the DIO notifying the acquired DODAG2 to another communication apparatus after the communication path is switched.

  As described above, according to the present embodiment, the communication path can be switched by using the most significant bit of the RPL Instance ID as the switching instruction information. The switching instruction information is not limited to this, and may be a rank value, a version number, DODAGID, or the like, for example.

  In the present embodiment, the DODAG information is used as switching instruction information. However, the DODAG information can also be used as route information and connection information in the first embodiment and the third embodiment. Thereby, the communication apparatus which concerns on 1st Embodiment and 3rd Embodiment is realizable.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. Further, for example, a configuration in which some components are deleted from all the components shown in each embodiment is also conceivable. Furthermore, you may combine suitably the component described in different embodiment.

1: communication data holding unit, 2: communication path storage unit, 3: communication path switching unit, 4: communication control unit, 5: switching instruction acquisition unit, 6: connection information collection unit, 10-14: communication device

Claims (9)

A communication device constituting a multi-hop network,
A switching unit that switches the communication path used for transfer of the communication data based on path information including an identifier that identifies a communication path to the route node and destination information that indicates a destination of communication data in the communication path; ,
A control unit that transfers the communication data to the destination of the communication path switched by the switching unit ;
When the switching unit acquires new route information, the switching unit switches the communication route used for transferring the communication data to the communication route indicated by the new route information,
The route device of route information indicated by the new route information is different from the route node of the communication route indicated by the route information . The route information includes priority information indicating the priority of the communication route,
When the switching unit acquires path information of a communication path having a higher priority than the communication path indicated by the path information , the switching path uses the communication path used for transferring the communication data as the communication path having the higher priority. The communication apparatus according to claim 1 , wherein the communication apparatus is switched to. The identifier, server address, the border router address, and a communication apparatus according to any one of claims 1 to 2 comprising at least one of the RPL instance ID. The destination information, the communication device according to any one of claims 1 to 3 containing the address of the transfer destination to become another communication device of the communication data. Further comprising: an obtaining unit obtaining a switching instructing switching instruction to a predetermined communication path, wherein the switching unit includes a communication route used for transfer of the communication data, designated by the switching instruction the acquisition unit has acquired a communication device according to any one of claims 1 to 4 to switch to the communication path. A collection unit for collecting connection information indicating connectivity of the communication path;
The switching unit, based on the collected connection information by the collecting unit, a communication device according to any one of claims 1 to 5 for switching a communication path to be used for transfer of the communication data. The switching unit, when it is determined that the unreachable the communication path in use on the basis of the connection information, the communication path to be used for transfer of the communication data, switches the connectable communication path based on the route information The communication apparatus according to claim 6 . The connection information communication apparatus according to claim 6 or claim 7 comprising at least one of the number and the ICMP error notification failed to transfer the communication data. A multi-hopping network comprising a plurality of communication devices according to any one of claims 1 to 8 .

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